Post for attaching snap fastener stud elements



Nov. 14, `1967 P. R. TARULLO POST FOR ATTACHING SNAP FASTENER STUD ELEMENTS Filed Oct. 22, 1965 United States Patent O 3,351,987 PQST FGR ATTACHENG SNAP FASTENER STUD ELEMENTS Pasquale R. Tarullo, Waterbury, Conn., assigner to Scovill Manufacturing Company, Waterbury, Conn., a corporation of Connecticut Filati st, 22, 1965, Ser. No. 501,727 1 Claim. (Cl. 24-219) ABSTRACT 0F THE DHSCLSURE An improved post for attaching a hollow stud element of a snap fastener unit has a tubular barrel which is necked inwardly near its open end to provide a ared end section with a sharp outer corner for shearing material as the lpost enters the stud. The flared end is not thinned out so that the convex section below the neck will rst collapse outwardly to make a secure attachment on thicker materials, while on thinner materials the ared end will also collapse to prevent buckling of the barrel.

This invention relates to the attaching of hollow snap fastener stud elements permanently to foundation material.

In the use of a post for attaching snap fastener stud elements, the hollow barrel of the post has usually been tapered and sharpened at the upper end so as to pierce through the material as it entered the hollow neck of the stud. Further endwise pressure collapsed the open end of the lpost inside the hollow stud. However, difficulties have been experienced in obtaining a uniform upsetting of the barrel end.

The deformation of the end would sometimes occur only on one side, resulting in a relatively Weak and not always secure attachment, particularly when the foundation material was heavy or comparatively thick. In other cases, when such posts were used with lighter foundations, the barrel would tend to collapse below the stud neck, sometimes creating a shear condition within the barrel length.

The post of the present invention provides -a zone of uniform weakness against upsetting pressures so that the collapsing occ-urs at the proper place inside the stud head. This results from an outwardly convex surface or Ibulge Ibelow the inwardly formed neck. This neck, near the upper open end of the barrel, also results in a greater degree of flare and a more uniform flare so as to provide a sharp edge at the outer corner for cutting through the foundation material.

In the accompanying drawing, I have shown for purpose of illustration, one embodiment which the invention may assume in practice. In the drawing, in which all figures lare sectional views:

FIG. 1 shows the post in position for application to the foundation material and attachment to the stud element of the snap fastener units;

FIG. 2 illustrates the piercing step in the operation;

FIG. 3 shows the beginning of the collapse or upsetting action;

3,35L987 Patented Nov. 14, 1967 ICC FIG. 4 shows the final result as applied to a thick foundation; :and

FIG. 5 illustrates the result with a thin foundation.

The snap fastener stud element -is of a common type having a base liange 6, a head 7 having an inwardly indented top 8 and a neck 9. This provides a constricted entrance opening 10 and an annular space 11 for receiving the end of the barrel of the post.

The post also has a base flange 12 and a barrel open at both ends and having a generally cylindrical wall 13 which extends perpendicularly from the base as distinguished from :a tapered barrel. Adjacent its upper end, the barrel is formed with an inwardly extending neck 14 so as to provide a fla-red end section 15 and a convex section 16. This results in a uniform ilare with an outer sharp corner 17 which preferably has a slightly greater overall diameter than the main body of the barrel 13. The diameter of this cutting edge is also slightly greater than that of the entrance opening 10 in the stud element so that it will cut through the foundation material 18 as indicated in FIG. I2.

As the post Ibarrel enters the annular space 11 of the stud, the flared end will jam against the stud wall and further pressure will start to collapse the post wall in the relatively weak zone caused by the convex section 16. This not only allows for uniform upsetting of the post wall in the proper place, but permits the use of one post barrel length on a wider range of thicknesses of the foundation material 18. With the relatively thicker foundations, as indicated in FIG. 4, there is ample collapsing of the wall at its weaker zone to provide secure holding, while with thinner foundations, as indicated in FIG. 5, the ared end collapses more tightly inside the annular space 11 allowing even more room for continued upsetting of the post in the region of the convex section 16.

What I claim is:

A post for attaching the hollowing stud element of a snap fastener unit, said post comprising a ibase flange and an open ended barrel with a generally cylindrical wall, said wall having an inwardly formed neck adjacent its upper end to provide a flared end section at the open end of the barrel and a convex section below said ilaIed end section, said convex section providing a zone of uniform weakness when endwise pressure is applied'to the barrel to cause the barrel to -collapse outwardly in said zone, wherein the thickness of said barrel wall including said ilared end section is substantially uniform throughout, and wherein the outer corner of said ared end Section is relatively sharp to provide a cutting edge for shearing material, the outside diameter of the barrel at said outer corner being substantially the same as the outside diameter of the cylindrical portion of the barrel.

References Cited UNITED STATES PATENTS 557,704 4/ 1896 Richardson 24-21-7 650,379 5/1900 Dowse 24-214 1,583,472 5/1926 King 24-219 WILLIAM FELDMAN, Primary Examiner.

E. SIMONSEN, Assistant Examiner. 

